Nucleic acids are used frequently in the clinical setting in, for example, the identification of genetic mutations and in the diagnosis of bacterial and/or viral infections. In general, such methods have used nucleic acids isolated or extracted from biological samples.
The most commonly used method for isolating DNA from a biological sample (e.g., blood) involves lysing the cells contained in the sample with a combination of a proteolytic enzyme and a detergent followed by extracting the mixture with an organic solvent, e.g., phenol and chloroform, so that the DNA enters the aqueous phase and the protein enters the organic phase. The DNA in the aqueous phase is then concentrated by alcohol precipitation and resuspended in a suitable volume for analysis. Such methods are, however, time-consuming and require the use toxic reagents.
Methods of stabilizing DNA in body fluids are known (e.g., U.S. Patent Application Publication No. 2003-104251).